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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Manufacturing Nondestructive Evaluation Final Report CRADA No. TC-0351-92

The goaI of this project is the design, test, and fielding of automated NDE systems throughout the KTC. In the casting plant, activities were divided into four tasks i) development of quantitative tools for calculating measures of porosity by area from digital radiographic (DR) images, ii) upgrade of existing digital radiographic equipment (non-functional in 1995), iii) design and fielding of an on-the-floor unit capable of digital radiography for aluminum parts as an unattended “baggage scanner” (working with VIJAY technologies on this effort), and iv) connecting digital radiographic results to a central database which includes shot profiles, die temps, and metal temps from the pressure die casting machines.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Powder bed binder jet 3D printing of Inconel 718: Densification, microstructural evolution and challenges

Traditional manufacturing of Inconel 718 components from castings and thermomechanical processing routes involve extensive post processing and machining to attain the desired geometry. Additive manufacturing (AM) technologies including direct energy deposition (DED), selective laser melting (SLM), electron beam melting (EBM) and binder jet 3D printing (BJ3DP) can minimize scrap generation and reduce lead times. While there is extensive literature on the use of melting and solidification based AM technologies, there has been limited research on the use of binder jet 3D printing. In this paper, a brief review on binder jet additive manufacturing of Inconel 718 is presented. In addition, existing knowledge on sintering of Inconel 718 has been extended to binder jet 3D printing. We found that supersolidus liquid phase sintering (SLPS) is necessary to achieve full densification of Inconel 718. SLPS is sensitive to the feedstock chemistry that has a strong influence on the liquid volume fraction at the processing temperature. Based on these results, we discuss an empirical framework to determine the role of powder particle size and liquid volume fraction on sintering kinetics. In conclusion, the role of powder packing factor and binder saturation on microstructural evolution is discussed. The current challenges in the use of BJ3DP for fabrication of Inconel 718, as well as, extension to other metal systems, are presented.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Tunable photoluminescence of CsPbBr{sub 3} perovskite quantum dots for light emitting diodes application

All-inorganic cesium lead halide (CsPbBr{sub 3}) perovskite quantum dots (QDs), as one kind of promising materials, have attracted considerable attention in optoelectronic applications. Herein, we synthesized the colloidal CsPbBr{sub 3} QDs with tunable photoluminescence (PL) (493–531 nm) by adjusting the reaction temperatures, which revealed narrow emission bandwidths of about 25 nm. The average diameters of the QDs could be adjusted from 7.1 to 12.3 nm as the temperature increased from 100 °C to 180 °C. Moreover, the radiative lifetimes of CsPbBr{sub 3} QDs were measured to be ~ 2 ns, and the single QD fluorescence intensity time trace results demonstrated its suppressed blinking emission. Moreover, green light emitting diodes by using CsPbBr{sub 3} QDs casted on blue LED chips were further fabricated, which provided potential applications in the field of display and lighting technology. - Graphical abstract: The graphical abstract shows photoluminescence spectra of CsPbBr{sub 3} quantum dots and one typical light emitting diodes device (inset: schematic diagram and optical image). Display Omitted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1984

Use of adaptive walls in 2D tests

A new method for computing the wall effects gives precise answers to some questions arising in adaptive wall concept applications: length of adapted regions, fairings with up and downstream regions, residual misadjustments effects, reference conditions. The acceleration of the iterative process convergence and the development of an efficient technology used in CERT T2 wind tunnels give in a single run the required test conditions. Samples taken from CAST 7 tests demonstrate the efficiency of the whole process to obtain significant results with considerations of tridimensional case extension.

Archambaud, J. P.↗
DOE OSTI2017

Structural Mass Saving Potential of a 5-MW Direct-Drive Generator Designed for Additive Manufacturing

As wind turbine blade diameters and tower height increase to capture more energy in the wind, higher structural loads results in more structural support material increasing the cost of scaling. Weight reductions in the generator transfer to overall cost savings of the system. Additive manufacturing facilitates a design-for-functionality approach, thereby removing traditional manufacturing constraints and labor costs. The most feasible additive manufacturing technology identified for large, direct-drive generators in this study is powder-binder jetting of a sand cast mold. A parametric finite element analysis optimization study is performed, optimizing for mass and deformation. Also, topology optimization is employed for each parameter-optimized design.The optimized U-beam spoked web design results in a 24 percent reduction in structural mass of the rotor and 60 percent reduction in radial deflection.

17 WIND ENERGY↗
DOE OSTI2018

USHPRR FUEL FABRICATION PILLAR: FABRICATION STATUS, PROCESS OPTIMIZATIONS, AND FUTURE PLANS

The Fuel Fabrication (FF) Pillar, a project within the U.S. High Performance Research Reactor Conversion program of the National Nuclear Security Administration’s Office of Material Management and Minimization, is tasked with the scale-up and commercialization of high-density monolithic U-Mo fuel for the conversion of appropriate research reactors to use of low-enriched fuel. The FF Pillar has made significant steps to demonstrate and optimize the baseline co-rolling process using commercial-scale equipment at both the Y-12 National Security Complex (Y-12) and BWX Technologies (BWXT). These demonstrations include the fabrication of the next irradiation experiment, Mini-Plate 1 (MP-1), and casting optimizations at Y-12. The FF Pillar uses a detailed process flow diagram to identify potential gaps in processing knowledge or demonstration, which helps direct the strategic research agenda of the FF Pillar. This paper describes the significant progress made toward understanding the fuel characteristics, and models developed to make informed decisions, increase process yield, and decrease lifecycle waste and costs.

Wight, Jared M.↗
NASA NTRS2002

Mechanical Testing of IN718 Lattice Block Structures

Lattice block construction produces a flat, structurally rigid panel composed of thin ligaments of material arranged in a three-dimensional triangulated truss-like structure. Low-cost methods of producing cast metallic lattice block panels are now available that greatly expand opportunities for using this unique material system in today's high-performance structures. Additional advances are being made in NASA's Ultra Efficient Engine Technology (UEET) program to extend the lattice block concept to superalloy materials. Advantages offered by this combination include high strength, light weight, high stiffness, and elevated temperature capabilities. Recently under UEET, the nickel-based superalloy Inconel 718 (IN718) was investment cast into lattice block panels with great success. To evaluate casting quality and lattice block architecture merit, individual ligaments, and structural subelement specimens were extracted from the panels. Tensile tests, structural compression, and bending strength tests were performed on these specimens. Fatigue testing was also completed for several bend test specimens. This paper first presents metallurgical and optical microscopy analysis of the castings. This is followed by mechanical test results for the tensile ligament tests and the subelement compression and bending strength tests, as well as for the fatigue tests that were performed. These tests generally showed comparable properties to base IN718 with the same heat treatment, and they underscored the benefits offered by lattice block materials. These benefits might be extended with improved architecture such as face sheets.

Krause, David L.↗
DOE OSTI2023

Performance and durability of electrically conductive tape for shingled Si heterojunction technology cells

We report electrically conductive tape (ECT) was characterized and used to assemble shingled cell strings at low temperature to achieve high reliability Pb- and Ag-free interconnections. The volume resistivity for two considered ECTs are 0.13 ± 0.06 mΩ·cm and 0.47 ± 0.20 mΩ·cm and specific contact resistances, 6.85± 2.00 mΩ·cm 2 and 6.30 ± 0.37 mΩ·cm 2 using the emerging IEC 62788-8-1 Technical Specification for assessment of electrically conductive adhesives (ECA). Durability and performance of the technology in glass–glass mini modules were evaluated with temperature cycling, damp heat testing, and combined-accelerated stress testing (CAST). Through temperature cycling (-40°C to 85°C) applying five times the mini module short-circuit current in forward bias and in the multi climate CAST protocol, there was negligible degradation of fill factor after replacing connectors at the modules' cable leads; however, CAST resulted in short circuit current loss attributed to degradation in light collection by the cells, not the ECT. The IEC 61215-2 85°C, 85% relative humidity damp heat testing showed susceptibility of the HJT cells to effects of humidity in the electroluminescence intensity around the module perimeter that degraded power performance by 4% (relative). Contrasting the IEC 61215-2 qualification testing-based damp heat testing with CAST, factors such as the optical stress of CAST may precipitate the degradation of the modules whereas the humidity levels and duration of IEC 61215-2 damp heat testing may lead to excessive levels of humidity diffused into the modules, potentially resulting in degradation that is unrepresentative of the field.

14 SOLAR ENERGY↗
DOE OSTI2022

High-Pressure Characterization of Two Stereoisomers of Tetranitroester Cyclobutane

The high-pressure behavior of two stereoisomeric cyclobutane nitric ester materials were studied at room temperature to near 25 GPa via Raman spectroscopy and powder X-ray diffraction. The materials investigated included [cis-trans-cis]- and [all-cis]-tetranitrate ester cyclobutanes. Over the course of these studies no evidence of polymorphism was observed, highlighting the stability of the ambient pressure crystal structures of the cyclobutanes to conditions near the detonation pressure of the material. Differences were observed between the bulk moduli of the two stereoisomers, suggesting potential tunability in materials response under dynamic conditions through the use of isomeric materials. Finally, such findings suggest that these high-performance materials can serve as TNT replacement in novel melt-castable energetic formulations without the concern of uncontrolled polymorphism that might otherwise affect the performance and safety of a munition.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
NASA NTRS1982

Analysis, design, and test of a graphite/polyimide Shuttle orbiter body flap segment

For future missions, increases in Space Shuttle orbiter deliverable and recoverable payload weight capability may be needed. Such increases could be obtained by reducing the inert weight of the Shuttle. The application of advanced composites in orbiter structural components would make it possible to achieve such reductions. In 1975, NASA selected the orbiter body flap as a demonstration component for the Composite for Advanced Space Transportation Systems (CASTS) program. The progress made in 1977 through 1980 was integrated into a design of a graphite/polyimide (Gr/Pi) body flap technology demonstration segment (TDS). Aspects of composite body flap design and analysis are discussed, taking into account the direct-bond fibrous refractory composite insulation (FRCI) tile on Gr/Pi structure, Gr/Pi body flap weight savings, the body flap design concept, and composite body flap analysis. Details regarding the Gr/Pi technology demonstration segment are also examined.

Graves, S. R.↗
DOE OSTI2024

Enable superior performance of ultra-high loading electrodes through the cost-efficient solvent-free electrode manufacturing technology

This research explores an innovative solvent-free method for fabricating ultra-high loading NMC811 and graphite electrodes (~6mAh∙cm -2 ), showcasing remarkable electrochemical performance enhancements compared to the electrodes prepared by the conventional slurry-casting method. Here, the optimized microstructure with dry-printed (DP) electrodes enhanced electrolyte penetration and minimized lithium-ion diffusion tortuosity resulting in improved rate performance at high current rates. Additionally, this innovative electrode manufacturing approach enables more uniform CEI and SEI formation and growth, which effectively doubles the cycle life of single-layer pouch cells with DP electrodes. Beyond the performance enhancements, this method also offers a notable 29.2 % overall cost advantages, potentially revolutionizing future battery manufacturing. The findings presented in this work underscore the potential of solvent-free manufacturing technology as a high-loading capable and cost-efficient path for advanced battery production.

25 ENERGY STORAGE↗
NASA NTRS1972

Optimization in the design of a 12 gigahertz low cost ground receiving system for broadcast satellites. Volume 1: System design, performance, and cost analysis

The technical and economical feasibility of using the 12 GHz band for broadcasting from satellites were examined. Among the assigned frequency bands for broadcast satellites, the 12 GHz band system offers the most channels. It also has the least interference on and from the terrestrial communication links. The system design and analysis are carried out on the basis of a decision analysis model. Technical difficulties in achieving low-cost 12 GHz ground receivers are solved by making use of a die cast aluminum packaging, a hybrid integrated circuit mixer, a cavity stabilized Gunn oscillator and other state-of-the-art microwave technologies for the receiver front-end. A working model was designed and tested, which used frequency modulation. A final design for the 2.6 GHz system ground receiver is also presented. The cost of the ground-terminal was analyzed and minimized for a given figure-of-merit (a ratio of receiving antenna gain to receiver system noise temperature). The results were used to analyze the performance and cost of the whole satellite system.

Ohkubo, K.↗
NASA NTRS1977

Energy requirement for the production of silicon solar arrays

An assessment of potential changes and alternative technologies which could impact the photovoltaic manufacturing process is presented. Topics discussed include: a multiple wire saw, ribbon growth techniques, silicon casting, and a computer model for a large-scale solar power plant. Emphasis is placed on reducing the energy demands of the manufacturing process.

Lindmayer, J.↗
NASA NTRS1982

Interim review of the Energy Efficient Engine /E3/ Program

The NASA-sponsored Energy Efficient Engine (E3) Program, which is now in its fourth year, is assessed from the viewpoint of one of its research contractors. Attention is given to the development status of the shroudless fan, segmented combustor and exhaust mixer components which are encompassed by the program. The shroudless fan blades are two-thirds hollow for lightness, and are fabricated by means of plies and cores subjected to hot isostatic pressing diffusion bonding. The combustor's segmented liner is cast from turbine blade materials. Exhaust mixer flow visualization tests are described. Consideration is given to the effects of integrating the technology described with the low and high pressure advanced turbines whose development is also part of the E3 program.

Gardner, W. B.↗
NASA NTRS2000

Characterizing the Use of Ultrasonic Energy in Promoting Uniform Composite Growth in Immiscible Alloys

The results of experimental investigation and mathematical modeling for immiscible alloys subjected to ultrasonic influence are presented. It is known that in inoculated light alloy melts, ultrasonic treatment creates a new type of cast structure with extremely fine grains of uniform composition. This effect is produced across a wide range of freezing rates and technologies. However, it has not been demonstrated that the process can be successfully applied during controlled directional solidification processing. In this work we present the results from a set of directional solidification experiments and suggest describing the droplet size versus ultrasonic frequency and amplitude using an energy approach, followed with a more detailed analysis through numerical modeling of the ultrasonic field.

Grugel, Richard N.↗
DOE OSTI2017

Nitrate Salt Based Melt Cast Materials

Three new low melting compositions have been developed here based on the ingredients amino-1,2,4-triazolium nitrate, 3,5-diamino-1,2,4-triazolium nitrate and ammonium nitrate, to create the formulation AAD, in addition to mixtures comprising guanidinium 5-amino-tetrazolate and ammonium nitrate in either a 1 : 3 or 1 : 6 mole ratio (GAN13 and GAN16 respectively). The materials melt in the range of 95–100 °C and do not begin to decompose until >195 °C. The formulations are insensitive to impact, spark and friction and were calculated to show promising explosive performance properties (V D =8.78–9.0 km/s, P CJ =28.4–30.6 GPa). HMX mixtures of AAD, GAN13 and GAN16 were also prepared and these materials were characterized with respect to their safety and performance as well.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗